/*
 * Created on 2005-10-26
 *
 * TODO ������֤ͼƬר��
 * Ϊ�����JSP���ͼƬʱ���ֵ�
 * java.lang.IllegalStateException: getOutputStream() has already been called for this response
 * ����
 */
package com.jeff.Servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * @author Administrator
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class CreateImage extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public CreateImage() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("image/jpeg");
		
		response.setHeader("Pragma","No-cache");
		response.setHeader("Cache-Control","no-cache");
		response.setDateHeader("Expires", 0);

		int width=60, height=20;
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

		Graphics g = image.getGraphics();

		Random random = new Random();

		g.setColor(getRandColor(200,250));
		g.fillRect(0, 0, width, height);

		g.setFont(new Font("Times New Roman",Font.PLAIN,18));

		g.setColor(getRandColor(160,200));
		for (int i=0;i<155;i++)
		{
		        int x = random.nextInt(width);
		        int y = random.nextInt(height);
		        int xl = random.nextInt(12);
		        int yl = random.nextInt(12);
		        g.drawLine(x,y,x+xl,y+yl);
		}

		String sRand="";
		for (int i=0;i<4;i++){
		    String rand=String.valueOf(random.nextInt(10));
		    sRand+=rand;
		    g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//???????????????????????????????
		    g.drawString(rand,13*i+6,16);
		}

		HttpSession session = request.getSession(true);
		session.setAttribute("rand",sRand);

		g.dispose();

		ImageIO.write(image, "JPEG", response.getOutputStream());
	}

	private Color getRandColor(int fc,int bc){
        Random random = new Random();
        if(fc>255) fc=255;
        if(bc>255) bc=255;
        int r=fc+random.nextInt(bc-fc);
        int g=fc+random.nextInt(bc-fc);
        int b=fc+random.nextInt(bc-fc);
        return new Color(r,g,b);
        }

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occure
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}
